Well, being an animal lover myself and owning a couple of cast off cats (nobody wanted) I can relate.
I don't have any advice other than:
Take her to the cat clinic in Hamilton for a second opinion if needed.
www.thecatclinic.ca
The vet who runs the place is one of 3 "cat practitioners" in Canada. (Basically a vet who has trained over and above in the cat field.)
Dr. Obrien.
I've taken my cats there and the clinic is very well run, clean, and Obrien is truly great.
Word of caution, though, if you phone to make an appointment, you have to INSIST that you are to see Obrien. There are 2 other fucking bitches who work there (the dark haired one is the worst - a complete "I'm so much smarter than you" fat dyke. Avoid her like the plague. She is so condescending it will make you sick.
There is a guy who works there - Camaleri who is very good too.
But for the real PRO advice and service, insist on Obrien.
Just as an aside on vets. I once was asked by a vet in Toronto in Etobicoke to give him a quote to do some work to his building. I went "in the back" and it was a HORROR SHOW. Dirty, unorganized, animals stacked in cages on top of one another. I'd never take my cat there. I couldn't believe what I saw. Your cat would be better off with you treating her yourself than taking her to that hell-hole.
At least the Cat Clinic in Hamilton is very clean, and organized. They will also let you visit your cat if she's in the hospital.